Moonstone Alchemy vs Brassy Brass

How close are they?

ΔE 7.8, close: similar, with a visible difference side by side. Brassy Brass is more muted, cooler than Moonstone Alchemy.

Can I use Brassy Brass instead of Moonstone Alchemy?

Usually, if you are not matching paint already on the model. Close match (ΔE 8). Brassy Brass is more muted, cooler than Moonstone Alchemy.

Can I use Moonstone Alchemy instead of Brassy Brass?

The same difference applies the other way round: Moonstone Alchemy is more saturated, warmer.

ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.